New filter...

dombey · Feb 27, 2012

So this weekend I took the plunge and opened up my DE filter for the first time since we bought the house, and I'm guessing it was the first time it had EVER been opened. I intended to clean the internals, which I did, but then decided before reassembly that it was pointless since all of the leaves were missing about 25%of their mesh...
I wanted to switch to a sand filter anyways because I hate dealing with DE.
Anyways, 48 hrs later I'm the proud new owner of a Hayward 30" sand filter that I installed myself and aside from some cosmetically challenged piping, it seems to run great.
The pool has been sitting idle for a few days and it was really windy today. You couldn't see the drain at the bottom in broad daylight (8' deep).
I turned the pump on and it started up around 18 psi but over about 30 mins it rises to 30+ psi. I backwash and it drops back down to 18. I've done this several times tonite and it seems pretty predictable and I assume this is going to be the norm until the water clears up... But I wanted to check and make sure I didn't screw something up that is causing the pressure to rise quicky...
Thoughts, feelings, encouragements?

Bones · Feb 27, 2012

Its a possibility that DE was leaking into the pool and the sand filter is pulling it out, that would make sense i believe. Not had that experience personally but have read a couple threads on here to that effect.

duraleigh · Feb 28, 2012

dombey,

Your sand filter is doing exactly what it is supposed to do.....filtering out junk from your pool, even though you may not be able to see it.

In your climate, I suspect you have a nice algae bloom starting up (yes, it can be invisible for a while) and that you may need to shock your pool. A complete set of test results would give us some more clues.

dombey · Feb 29, 2012

duraleigh said:
dombey,

Your sand filter is doing exactly what it is supposed to do.....filtering out junk from your pool, even though you may not be able to see it.

In your climate, I suspect you have a nice algae bloom starting up (yes, it can be invisible for a while) and that you may need to shock your pool. A complete set of test results would give us some more clues.

I think I'm clear on algae. Zero measurable FC loss yesterday (water is cold and overcast). That was with my FAS DPD kit at .5 granularity.
Where I do have issues is on TA (180 initially, now 160)... But I'm all over the acid/aeration cycle.

Melt In The Sun · Mar 1, 2012

If your pool is cloudy, there's about a 99% chance you have algae. I'd check again!

duraleigh · Mar 1, 2012

If it's not algae, your filter certainly appears to be clogging up with something. You'll simply have to keep backwashing each time the pressure rises until you can run the pump and the pressure holds steady. It should be longer and longer between backwashes as the water gets cleaner. :-D

dombey · Mar 1, 2012

So, I'm pretty sure it was a large amount of DE that got into the pool during the filter disassembly and swap. I had a bad backwash valve as well; it always pumped brown water into the pool...
The pool is definitely clearing up and the backwashes are much less frequent although overnight it is still building to 30 psi. It runs at 18 on a clean filter.
I'm out of town until Tuesday but I'll shock it when I return to make sure I'm clear.